The role of psychosocial factors in the development of breast carcinoma: Part II. Life event stressors, social support, defense style, and emotional control and their interactions

Background: The evidence supporting an association between life event stress and breast carcinoma development is inconsistent.

Methods: Five hundred fourteen women requiring biopsy after routine mammographic breast screening were interviewed using the Brown and Harris Life Event and Difficulties Schedule. Other psychosocial variables assessed included social support, emotional control, and defense style. Biopsy results identified 239 women with breast carcinoma and 275 women with benign breast disease. Multiple logistic regression analysis was used to distinguish between breast carcinoma subjects and benign breast disease controls based on these psychosocial variables and their interactions.

Results: The findings of the current study revealed a significant interaction between highly threatening life stressors and social support. Women experiencing a stressor objectively rated as highly threatening and who were without intimate emotional social support had a ninefold increase in risk of developing breast carcinoma.

Conclusions: Although there was no evidence of an independent association between life event stress and breast carcinoma, the findings of the current study provided strong evidence that social support interacts with highly threatening life stressors to increase the risk of breast carcinoma significantly. [See also accompanying article on pages 679-85, this issue.]